a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
67 lines
2.4 KiB
Text
67 lines
2.4 KiB
Text
=pod
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=head1 NAME
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SSL_CTX_set_cert_verify_callback - set peer certificate verification procedure
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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void SSL_CTX_set_cert_verify_callback(SSL_CTX *ctx, int (*callback)(X509_STORE_CTX *,void *), void *arg);
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=head1 DESCRIPTION
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SSL_CTX_set_cert_verify_callback() sets the verification callback function for
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I<ctx>. SSL objects that are created from I<ctx> inherit the setting valid at
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the time when L<SSL_new(3)> is called.
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=head1 NOTES
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Whenever a certificate is verified during a SSL/TLS handshake, a verification
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function is called. If the application does not explicitly specify a
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verification callback function, the built-in verification function is used.
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If a verification callback I<callback> is specified via
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SSL_CTX_set_cert_verify_callback(), the supplied callback function is called
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instead. By setting I<callback> to NULL, the default behaviour is restored.
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When the verification must be performed, I<callback> will be called with
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the arguments callback(X509_STORE_CTX *x509_store_ctx, void *arg). The
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argument I<arg> is specified by the application when setting I<callback>.
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I<callback> should return 1 to indicate verification success and 0 to
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indicate verification failure. If SSL_VERIFY_PEER is set and I<callback>
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returns 0, the handshake will fail. As the verification procedure may
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allow to continue the connection in case of failure (by always returning 1)
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the verification result must be set in any case using the B<error>
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member of I<x509_store_ctx> so that the calling application will be informed
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about the detailed result of the verification procedure!
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Within I<x509_store_ctx>, I<callback> has access to the I<verify_callback>
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function set using L<SSL_CTX_set_verify(3)>.
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=head1 WARNINGS
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Do not mix the verification callback described in this function with the
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B<verify_callback> function called during the verification process. The
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latter is set using the L<SSL_CTX_set_verify(3)>
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family of functions.
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Providing a complete verification procedure including certificate purpose
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settings etc is a complex task. The built-in procedure is quite powerful
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and in most cases it should be sufficient to modify its behaviour using
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the B<verify_callback> function.
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=head1 BUGS
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=head1 RETURN VALUES
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SSL_CTX_set_cert_verify_callback() does not provide diagnostic information.
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=head1 SEE ALSO
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L<ssl(3)>, L<SSL_CTX_set_verify(3)>,
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L<SSL_get_verify_result(3)>,
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L<SSL_CTX_load_verify_locations(3)>
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=cut
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